rkhunter version of the ubuntu package is currently
1.4.0, while the installer is version
The repo version of
0.49, while its installer is
Since security is a major concern for servers, what would be the best choice: install the latest version or my distribution's package, even if outdated?
You can combine the best of both worlds by installing the latest package available from your distribution:
rkhunter 1.4.4 and
chkrootkit 0.52 for Ubuntu (the packages’ dependencies are satisfiable in previous releases of Ubuntu). The safest approach is to download the packages manually, and install them with
dpkg -i or
gdebi. You’ll need to keep an eye on future updates to those packages manually, but then you’d have had to do that anyway if you’d used the upstream downloads.
You could get automatic upgrades from Ubuntu by adding the Aardvark repositories and pinning; that’s beyond the scope of this answer though.
Upgrading in both cases is quite useful as you mention, since both projects have added new security checks (in particular, Linux.Proxy.10 in